The present invention is directed to a housing for long-field lamps having interchangeable louver inserts, whereby one lock is provided for the mutual, releasable interlocking of the housing and louver insert.
German reference DE No. 28 33 913 CS discloses a lock for an interchangeable louver insert in a lamp housing. The lock has a U-shaped carrier having two free legs and a spring arm extending in the direction of the free ends between the legs. The lock has its free legs secured to the inside of at least one face wall of the housing. The spring arm, whose free end is designed as a gripping surface having catch shoulders offset therefrom at both sides, describes an acute angle with the legs and, when the louver insert is introduced into the housing, has its gripping surface slide past and over the upper edge of that end louver lamella of the louver insert that is proximate to it and has its latch shoulders interlocking under a counter-latch that is represented by bent-off, upper edge parts of this end louver lamella.
Such a lock has the advantage that, when the louver is inserted, it is invisible except for the free end of the spring arm that acts as a gripping surface and further that an optical irregularity for the light rays that are also reflected at this end louver lamella cannot occur. What is disadvantageous about such a lock, however, is the fact that the counter-latch formed by the upper, bent-over edge of the end louver lamella of the louver insert has a rigidly prescribed height of a louver lamellae for louver inserts that can be interchanged with one another.